1. Field
This disclosure relates to chairs and seats.
2. Description of the Related Art
Chairs are ubiquitous in modern western society. Chairs are in our houses, in our offices, in social places, in parks, and in vehicles like cars and buses. What constitutes a “comfortable” chair is different for every type of person, depending on their sensibilities and pre-conceived notions about comfort. In order to accommodate a variety of users, high quality office chairs, as well as the seats in high-end automobiles, and others, may provide a number of degrees of freedom to adjust features of the chair such as the height and width of the seat, the angle of the seat and the backrest, the shape of the seat, and the shape of the backrest with particular emphasis on support for the lower back. Massaging, heating, and cooling functions are also seen, as are inflatable lateral support cushions.
There may be a common misconception that being “relaxed” or “comfortable” implies remaining motionless. However, physical discomfort and stress can be caused by inactivity of muscle groups and by unvaried pressure on joints and other body structure. Thus frequent small motions, such as those that occur naturally while sleeping or when sitting in a non-steady environment, may be much more relaxing than remaining motionless.
One degree of freedom that is missing in current chairs and seats is the capability to allow the occupant to move or rotate their pelvis in a coronal or frontal plane. Rocking the pelvis in the coronal plane is a natural motion that occurs during walking and other physical activity. However, current chairs may constrain the pelvis to a fixed horizontal position. Another type of movement that is notably absent when sitting in current chairs is the balancing micro-movements that occur when standing and walking, or when sitting in a non-steady environment such as a boat or vehicle. Furthermore, the angle between the seatback and the sitting surface is fixed or at least cannot be changed at high frequencies as occur during spontaneous back and leg movements.
Throughout this description, elements appearing in figures are assigned three-digit reference designators, where the most significant digit is the figure number and the two least significant digits are specific to the element. An element that is not described in conjunction with a figure may be presumed to have the same characteristics and function as a previously-described element having a reference designator with the same least significant digits.